ML19114A316
| ML19114A316 | |
| Person / Time | |
|---|---|
| Site: | 07103052 |
| Issue date: | 03/05/2019 |
| From: | Willems T TN Americas LLC, Orano USA |
| To: | Division of Spent Fuel Management |
| Shared Package | |
| ML19115A128 | List:
|
| References | |
| DOS-18-011415-022-NPV, V2.0 | |
| Download: ML19114A316 (12) | |
Text
Formulaire : PM04-4-MO-6E rév. 02 Orano TN SAFETY ANALYSIS REPORT NON PROPRIETARY VERSION CHAPTER 1A TN MTR Prepared by T.WILLEMS Date Signature Identification :
DOS-18-011415-022-NPV Vers. 2.0 Page 1 / 12 NON PROPRIETARY VERSION STRUCTURAL STRENGTH OF INTERNAL FITTINGS OF THE TN-MTR PACKAGING AND THEIR CONTENTS TABLE OF CONTENTS REVISION STATUS
SUMMARY
- 1.
purpose
- 2.
CALCULATION METHODS
- 3.
CRITERIA
- 4.
CALCULATION MODEL
- 5.
BOUNDARY CONDITIONS
- 6.
RESULTS
- 7.
STRUCTURAL STRENGTH OF FUEL ELEMENTS
- 8.
STRUCTURAL STRENGTH OF MTR ELEMENT PACKING SYSTEMS
- 9.
CONCLUSION
- 10. REFERENCES APPENDIX 1A-1: Structural strength of the RHF internal fittings of the TN-MTR packaging and its content APPENDIX 1A-2:
Structural strength of the MTR-68 internal fittings of the TN-MTR packaging and its content APPENDIX 1A-3:
Structural strength of the MTR-52 internal fittings of the TN-MTR packaging and its content APPENDIX 1A-4:
Structural strength of the MTR-52S and MTR-52SV2 internal fittings of the TN-MTR packaging and its contents APPENDIX 1A-5:
Structural strength of the MTR-44 internal fittings of the TN-MTR packaging and its content APPENDIX 1A-10: Structural strength of the CESOX internal fittings APPENDIX 1A-11: Structural strength of the FRM-II basket and associated fuel elements APPENDIX 1A-12: Structural strength of plate fuel elements APPENDIX 1A-13: Structural strength of the caesium trap internal fittings APPENDIX 1A-14: Structural strength of the gisete internal fittings
Form: PM04-4-MO-6 rev.02 NON PROPRIETARY VERSION Orano TN Identification:
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2.0 Page 2 of 12 NON PROPRIETARY VERSION REVISION STATUS Revision Date Modifications Prepared by /
Checked by Old reference: DOS-16-00173678-102 6
N/A Document first issue. Revision number intentionally set to correspond to the source document revision number.
TWI / APA New reference: DOS-18-011415-022 1.0 N/A New reference due to new document management system software.
TWI / APA 2.0 N/A Adding of the Caesium trap content and Gisete content SAZ / TWI
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SUMMARY
This chapter and its appendices present mechanical calculations for the internal fittings of the TN-MTR packaging and their contents, to verify that stresses and strains are acceptable.
The applied load is derived from the analysis of the behaviour of the package model in drop cases representative of accident transport conditions, presented in Appendix 9 to Chapter 1.
Material properties are taken at the temperatures calculated in Chapter 2A.
The calculations are made either using finite element computer programs, or analytical calculations.
The results show that stresses in baskets for MTR type fuel elements taking account of dynamic amplification phenomena are acceptable and that strains are negligible, which validates assumptions made for the thermal calculations and the nuclear safety analysis.
It is also demonstrated that the geometry and integrity are maintained for RHF and FRM-II elements, and MTR fuel elements with flat or curved plates, for irradiated and non-irradiated elements, and the mechanical strength of wedge systems, canisters and BR2 cases is confirmed. This thus validates assumptions made for the nuclear safety analysis of the package The results demonstrate that the strength of the internal fittings of the CESOX content is guaranteed under routine transport conditions. The strength of the sealed double capsule containing radioactive material is guaranteed by the existence of a valid approval as a sealed source in special form.
The calculations demonstrate that the different components of the internal fittings of the caesium trap content necessary for the wedging of trap are sufficiently well designed under normal transport conditions. The calculations demonstrate also that the components of the fittings ensuring axial wedging of content are correctly well designed under accident transport conditions.
The calculations demonstrate that the different components of the internal fittings of the gisete content necessary for the wedging of isotopic generator are sufficiently well designed under normal transport conditions. The calculations demonstrate also that the components of the fittings ensuring axial wedging of content are correctly well designed under accident transport conditions.
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- 1. PURPOSE This document and its appendices present the mechanical analysis of possible contents of the TN-MTR packaging under normal and accident conditions of transport as defined by IAEA rules <1>.
This chapter includes several appendices, each appendix presenting the calculation of one of the baskets that can be used in the TN-MTR packaging with its worst case radioactive content, or the mechanical analysis of a special content (CESOX content and its internal fittings).
Appendix 12 to this chapter contains the justification of the mechanical strength of MTR type fuel elements with flat plates and the BR2 element with concentric plates during drop tests under accident transport conditions.
- 2. CALCULATION METHODS Calculations are made either analytically or using finite element computer programs. The following two programs are used:
ANSYS <2> for the analysis of the MTR-68, MTR-52 baskets, and part of the MTR-52S basket; IDEAS <3> for the analysis of the RHF, part of MTR-52S, MTR-44 and MTR-4 baskets.
- 3. CRITERIA The selected criteria must guarantee that assumptions made for the package thermal and radiation shielding calculations and for nuclear safety analysis are valid.
In general, it has to be checked that there are no broken cores or walls of basket compartments for MTR type fuel elements and that deformations of baskets, wedging systems, canisters or BR2 cases are low.
Criteria dependent on the computer codes used for each basket are given in the appendices to this chapter.
Since the components that provide mechanical strength for the MTR-52SV2 basket are the same as the components for the MTR-52S, the mechanical design of the MTR-52S described in Appendix 1A-4 will be valid for both the MTR-52S and the MTR-52SV2. The same applies for the check on the strength of MTR-52SV2 basket neutron absorbing components because their mechanical properties are at least equivalent to the mechanical properties of the borated aluminium used for the MTR-52S. On the other hand, stresses in neutron absorbing flats during a lateral drop of the packaging will be studied to take account of the difference in design between the two baskets, and particularly reductions in section in flats at overlaps. Measured accelerations for the MTR-52S basket will be used for this calculation.
Moreover, the mechanical properties of borated aluminiums considered in the appendices are conservative and are upper-bound values taking account of the aging phenomenon.
Form: PM04-4-MO-6 rev.02 NON PROPRIETARY VERSION Orano TN Identification:
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2.0 Page 5 of 12 NON PROPRIETARY VERSION Concerning fuel elements:
in flat plates of MTR fuel elements, maximum stresses in a lateral drop must remain within the elastic range.
in concentric elements (such as BR2, RHF, FRM-II), small plastic deformations are acceptable.
The connections between fuel plates and edge plates must be guaranteed during axial drops.
It will also be checked that the content of baskets and the internal fittings of the CESOX content maintain their integrity under routine transport conditions.
For the caesium trap content, it is justified that the integrity of components of the internal fittings for wedging the caesium trap is maintained under normal transport conditions. It is justified also that the integrity of components of the internal fittings for the axial wedging the content is maintained under accident transport conditions.
For the gisete content, it is justified that the integrity of components of the internal fittings for wedging the isotopic generator is maintained under normal transport conditions. It is justified also that the integrity of components of the internal fittings for the axial wedging the content is maintained under accident transport conditions.
- 4. CALCULATION MODEL 4.1 Geometric model The geometric model is specific to each basket and is presented in the appendix for the basket.
The calculation model for the RHF basket is a 3D model representing the basket structure.
The MTR-68, MTR-52, MTR-52S and MTR-44 baskets are modelled in two dimensions, by representing a radial section of the basket. A calculation is made for each disk type (stainless steel and borated aluminium).
4.2 Characteristics of materials Material characteristics are presented in Chapter 0A and its appendices.
- 5. BOUNDARY CONDITIONS Applied boundary conditions are derived from the analysis of the behaviour of the package model in drop cases representative of accident transport conditions, presented in Appendix 9 to Chapter 1. According to this appendix, the maximum accelerations measured on the packaging are:
Form: PM04-4-MO-6 rev.02 NON PROPRIETARY VERSION Orano TN Identification:
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2.0 Page 6 of 12 NON PROPRIETARY VERSION acceleration in the case of an axial drop:
acceleration in the case of a lateral drop:
Accelerations applied to analysis models are given below. They are calculated from packaging drop accelerations and dynamic amplification factors that vary from one basket to another.
Accelerations used for the RHF basket are as follows:
acceleration on the basket in the case of an axial drop:
acceleration on the basket in the case of a lateral drop: up to depending on the drop angle.
Accelerations used for the MTR-68 basket are as follows:
acceleration on the basket in the case of an axial drop:
acceleration on the basket in the case of a lateral drop:
Accelerations used for the MTR-52, MTR-52S and MTR-52SV2 baskets are as follows:
acceleration on the basket in the case of an axial drop:
acceleration on the basket in the case of a lateral drop:
Accelerations used for the MTR-44 basket are as follows:
acceleration on the basket in the case of an axial drop:
acceleration on the basket in the case of a lateral drop:
Accelerations used in the case of the CESOX content are for routine transport conditions based on the directive given in reference <6>.
Accelerations used for the FRM-II basket are as follows:
acceleration on the basket in the case of an axial drop:
acceleration on the basket in the case of a lateral drop:
Accelerations used in the case of the caesium trap and gisete contents correspond to accelerations are collected at the time of drops representative under normal transport conditions presented in Appendix 6 to chapter 1. Acceleration chosen in case of an axial drop under accident transport conditions is taken equal to.
- 6. RESULTS 6.1 RHF Basket The calculations show that the basket structure is sufficiently well designed for normal and accident transport conditions.
Displacement and strain calculations show that displacements and strains are negligible. Therefore the basket geometry described in Chapter 0A can be used for thermal calculations and for the nuclear safety analysis.
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2.0 Page 7 of 12 NON PROPRIETARY VERSION Stress calculations show that stresses remain below the minimum required yield stress for the basket steel given in Chapter 0A.
6.2 MTR-68 basket The calculations show that the load bearing disks are sufficiently well designed for normal and accident transport conditions.
Stress calculations in borated aluminium disks confirm the minimum characteristics taken from Chapter 0A are satisfactory.
6.3 MTR-52 basket The calculations show that the stainless steel load bearing disks are sufficiently well designed for normal and accident transport conditions. They are not deformed as a result of drops specified under normal and accident transport conditions.
Calculations of the mechanical strength of borated aluminium disks confirm that they are not deformed.
Calculations of the mechanical strength of BR2 cases (se chapter 1A-3-1) confirm that the BR2 cases guarantee the non-dispersion of matter under accident transport conditions.
6.4 MTR-52S and MTR-52SV2 baskets The calculations show that the load bearing disks and the stainless steel sleeves are sufficiently well designed for normal and accident transport conditions.
Calculations of the mechanical strength of neutron absorbing disks confirm that they are not deformed.
Calculations of the mechanical strength of canisters (see Chapter 1A-4) demonstrate that canisters always maintain confinement of the material after accident transport conditions.
6.5 MTR-44 basket The calculations show that the load bearing disks are sufficiently well designed for normal and accident transport conditions. It is checked that the stresses in disks are below the yield stress for the basket construction steel specified in Appendix 5 to Chapter 0A. It is also confirmed that there is no risk of buckling of steel and borated aluminium disks under normal and accident transport conditions.
6.6 CESOX content and its specific internal fittings The calculations demonstrate that the integrity of the internal fittings for wedging the CESOX content is maintained under routine transport conditions. The strength of the sealed double capsule containing radioactive material is guaranteed by the existence of an approval as a sealed source in special form, valid at the time of the transport.
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2.0 Page 8 of 12 NON PROPRIETARY VERSION 6.7 FRM II Basket The calculations show that the different parts of the FRM-II basket are sufficiently well designed for normal and accident transport conditions.
Therefore the basket geometry described in Chapter 0A can be used for thermal and radiation shielding calculations and for the nuclear safety analysis.
6.8 Caesium trap content and its specific internal fittings The calculations show that the different components of the internal fittings necessary for the wedging of trap are sufficiently well designed under normal transport conditions. The calculations demonstrate also that the components of the fittings ensuring the axial wedging of content are correctly well designed under accident transport conditions.
6.9 Gisete content and its specific internal fittings The calculations show that the different components of the internal fittings necessary for the wedging of isotopic generator are sufficiently well designed under normal transport conditions. The calculations demonstrate also that the components of the fittings ensuring the axial wedging of content are correctly well designed under accident transport conditions.
- 7. STRUCTURAL STRENGTH OF FUEL ELEMENTS The mechanical characteristics used for the calculations are applicable to non-irradiated materials. It was demonstrated in note <4> that the mechanical properties of irradiated materials are better than the properties of non-irradiated materials. Therefore it is conservative to use data for non-irradiated materials, instead of the real properties of the materials.
7.1 RHF elements The calculation presented in Section 7 in Appendix 1 to Chapter 1A demonstrates that RFH elements maintain their geometry and their integrity after accident transport conditions. This demonstration validates basic assumptions about the integrity of the fuel, on which the nuclear safety analysis of the package is based.
7.2 MTR elements with flat plates (generic, ORPHEE, OSIRIS, ANSTO) and BR2 The mechanical strength criterion to be verified before transport according to Chapter 0A, is justified in Appendix 12 to this Chapter for MTR elements with flat plates. The mechanical strength of flat plates under accident transport conditions is confirmed.
In the case of the following elements:
OSIRIS U3Si2 transported in the MTR-68, MTR-44, MTR-52, MTR-52S and MTR-52SV2 baskets;
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2.0 Page 9 of 12 NON PROPRIETARY VERSION ORPHEE transported in an MTR-68 or MTR-44 type basket; ANSTO transported in and MTR-68, MTR-52S or MTR-52SV2; it is demonstrated that the mechanical strength criterion is respected for an aluminium cladding (AG2-NET, AG3-NET or 6061 depending on the elements) depending on the thermal power of the element, thus making it unnecessary to check compliance with the mechanical criterion before transport.
The strength of the BR2 element with concentric plates is also confirmed in this appendix by digital calculations.
7.3 FRM-II elements The calculation presented in Appendix 11 to Chapter 1A demonstrates that FRM-II elements maintain their geometry and their integrity after accident transport conditions. This demonstration validates assumptions (integrity of the fuel after accident conditions) on which the nuclear safety analysis of the package is based.
- 8. STRUCTURAL STRENGTH OF MTR ELEMENT PACKING SYSTEMS Fuel element wedging systems must be used to assure that active parts of some contents of the MTR68, MTR52, MTR44, MTR52S and MTR52SV2 baskets do not protrude under normal and accident conditions. There are 7 different types of spacers thus defined and authorized for transport in the TN-MTR packaging, as described in Chapter 0A.
The mechanical strength of these spacers should be verified under accident transport conditions.
8.1 Mechanical strength of wedging systems The only case harmful for the integrity of the spacers is an axial drop, the force applied being due to the mass of the fuel element.
The mass selected for the fuel elements is M = 21 kg. This mass upper-bounds the mass allowed in the multi-compartment baskets of the TN-MTR packaging.
Acceleration in the case of an axial drop on the bottom of the packaging is:
p = (see Chapter 1-9).
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2.0 Page 10 of 12 NON PROPRIETARY VERSION The maximum force resisted by the bottom spacer is then:
Fp = M x p = 21x9,81x =
Acceleration in the case of an axial drop on the shock absorbing cover is equal to t = (see chapter 1-9).
The maximum force resisted by the top spacer is then:
Ft = M x t = 21x9,81x =
The integrity of the spacers is checked by considering the compression strength. The selected criterion is that the following relation must be respected:
< +
2 The selected criterion for aluminium alloy spacers is conservatively as follows:
At 200°C, the mechanical properties of the materials commonly used for manufacturing spacers are as follows:
stainless steel (type A) Rei = 118 MPa and Rmi = 360 MPa (see chapter 0),
aluminium alloy: Rea = 80 MPa (upper-bound value for a material in the 2000 to 5000 series - Tab XVII, Chapter M447 in Engineering Techniques).
Furthermore, concerning aging of aluminium grades, reference <5> shows that after 10,000 h (416 days) at 260°C, all aluminium grades in the 2000 to 5000 series still have a yield stress of more than 20 MPa. The value of 20 MPa is used conservatively.
We can thus determine the minimum cross-sections of spacers based on the strength formula:
for steel spacers: >
2x
+
for aluminium spacers: >
S min (mm²)
Bottom spacer Top spacer Stainless steel
> 276
> 128 Aluminium alloy
> 3306
> 1535
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2.0 Page 11 of 12 NON PROPRIETARY VERSION 8.2 Definition of allowable wedging systems Spacers for fuel elements must respect the following criteria:
Their stress area must be greater than the values below considering the material from which they are manufactured:
- 276 mm² for stainless steel bottom spacers,
- 3306 mm² for aluminium alloy bottom spacers,
- 128 mm² for stainless steel top spacers,
- 1535 mm² for aluminium alloy top spacers, the stress areas of the 7 types of spacers presented in Chapter 0A are summarised in the following table:
Type Profile of the stress area Cross-section (mm²)
Materials Spacer type 1
2 angles - 80 46 3 738 Stainless steel Top / Bottom 2
2 angles - 70 40 3 642 3
Tube 83 min 50
> 3,447 Aluminium alloy 4
Tube 60.3 3.65 thick 649 Stainless steel 5
2 crossed flats 844 656 6
Tube 73 5 thick 1,068 7
Flats 836.5 24.5 2 174 (*)
Top
(*) The minimum area that supports the mass of a fuel element is:
plaque logement e
l S
2 174mm 2
87 S
8.3 Conclusion Sections of spacers defined and represented in Chapter 0A upper-bound the minimum sections presented above. Therefore the function of these spacers is maintained even under accident transport conditions.
Models 1 to 6 may be used as either top or bottom spacers. Short top spacers may be connected to each other to make it easier to put them into position.
lcompar eplate
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- 9. CONCLUSION Mechanical calculations of the strength of baskets, their contents, wedging systems, canisters and BR2 cases presented in this chapter and its appendices demonstrate that stresses in the baskets are acceptable, that basket and wedging system deformations are acceptable and that the integrity of the contents, baskets, canisters and BR2 cases is maintained.
Therefore this analysis shows that the geometries of baskets, their contents, spacers, canisters and BR2 cases described in the appendices to chapter 0A are the geometries that should be considered for thermal and radiation shielding calculations and for the nuclear safety analysis.
- 10. REFERENCES
<1> Applicable IAEA regulations: See Chapter 00
<2> ANSYS Engineering Analysis System Users Manual, Volumes 1 to 4, Revision 5.2.
<3> Finite Element Calculation Software - I-DEAS Master Series V6 A m1 developed by SDRC.
<4> TN International Note, << Justification of the strength of irradiated MTR elements under accident transport conditions >>, reference 4466-B-38 Revision 0.
<5> J. Gilbert KAUFMAN "Properties of Aluminium Alloys - Tensile, Creep, and Fatigue Data at High and Low Temperatures", First Edition, December 1999.
<6> IMO/OIT/EEC-UNO directive for loading cargoes in transport equipment.